In presence of anisotropic pairing, as in 2H-NbSe\(_2\) , we can take into account the hexagonal symmetry of the crystalline lattice by using [1]}
\(\Delta _a(\mathbf {r}) = c_a \Delta _0 \tanh (r/\xi _V) e^{-i \theta } \cos 6\theta .\) 
